Carburetor



J. s. sALvA CARBURETOR Sept. 11, 1928.. Y ,1,684,246

Filed Feb. s, 192e 2 sheets-sheet 2 Patented Sept. 11, 1928.

AUNITED STATES PATENT OFFICE.

JOHN SLSALVA,r OF LATONIA., KIEI'JJUCKY,y ASSIGNOR TO THE SALVA CARBURETER COMPANY, OF COVINGTON, KENTUCKY, A CORPORATION OF KENTUCKY.

CARBURETOR.

`.Application filed Ielnuaryv 8, 1926. Serial No. 86,825.

One feature of carburetor performance that is not recognized by automotive engineers generally is that thefuel supplied to an internal combustion engine by means of a carburetor is not always vaporized in the carburetor. On the contrary, With the majority of carburetors heretofore in use, the fuel is'drawn into the air stream by the suction of the engine piston, and is carried With the air into. the cylinder in a liquid state. Sometimes, but not always, the fuel is supported by the air stream in the lform of minute drops suspended therein. The generally accepted idea that a carburetor is a vaporizing device may easily be shovvn to be a fallacy by inserting a short length of clear glass tubing between the carburetor and the branched portion of the engine manifold. This `Will' show that the fuel passes to the engine cylinder in liquid form, usually swirling about and enveloping the air stream, clinging to the inner surface of the inlet manifold.

Those carburetor engineers Who have 5 recognized this peculiarity of the air-fuel mixture when passing from the carburetor to the engine cylinder, have devised various methods for the purpose of securing a more intimate mixture of the fuel `with the air While the fuel is passing'through the carburetor, andof maintaining the mixture intact While it is on its Way from the carburetor to the engine cylinder. These methods have included air-bleedersof various designs, and generallyof such construction that a small stream vof air Will meet the fuel as it passes from the float chamber of the carburetor on its Way to the point Whereit meets the main air stream in the co-called :mixing chamber ofthe carburetor.

This method has proven eiiicacious to a certain degree and is employed in a number of Well-known makesv of carburetor. In fact, the air-bleeder yinto thefuel stream Was the subject of an extended litigation based Aon the presumably fundamental patent to G. V. Ahara, No. 684,662. But in all carburetors employing the basi-c princ'iple of the Ahara patent, and modifications thereof, the air meets the fuel after the .latte-r. has entered the fuel passage on its Way from the Float chambed to the mixing chamber. The Ahara method, While it vshovvsa decided Vimprovement in carburetor performance as compared to carburetors not so fitted, does not fully meet the requirement mixture. A number of methods of heating i the fuel or the air or the fuel-air mix-ture have been employed heretofore. These heating means include passing the air supply to the carburetor through a stove surrounding the exhaust pipe of the engine, jacketing the air passages with hot exhaust gases or with hot .Water from the kengine jacket, and the application of heat by means of electric current from a storage batteryor other source. But many of these vmethods have failed of their purpose, the maintaining'of the fuelin the form of a vapor after it ,leaves the carburetor and until. it enters the engine cylinder. The efficient application of heating means to the fuel is essential vvhen operating an engine with the fuels of a specific gravity below that of commercialgasoline, and when the engine is operated upon the Otto cycle.

The main,V object of this invention is to form an intimate mixture of the fuel lwith a small proportion of initial air, the mixing of the two taking place at the point Where the fuel leaves the float chamber and enters the passage through which it is about to pass from the float chamberV to the mixing chamber of a carburetor. Another object of my inventionl is to provide a means of heating 4the mix-ture of fuel and initial air as it -is passing from the `float .chamber to the mixing chamber. Another object `of my invention is to provide a passagel of appreciable length Within a small space, in Which passage the .mixture of fuel and ,inzitial ,air may be passed ,over a surface of sufficient area to absorb the requisite, quantity of heat. With these and other objects not specifically mentioned in view, my .invention consists certain combinations,

constructions and parts which will be hereinafter described and specifically pointed out in the claims hereunto appended.` In the accompanying drawings which form a part of this specification;

Fig. 1 is a sectional elevation along the line 1-1 of Fig. 2.

Fig. 2 is a sectional elevation along the line 2-2 of Fig. 1.

Fig. 3 is a perspective of the heating drum Y with the outer shell thereof partially broken away to show the helical grove forming the helical passage for the mixture of fuel and initial air. This ligure shows the heater considerably enlarged.

Fig. 4 is an enlarged fragmentary section taken along the same plane as Fig. 1. It

isdesigned to show more clearly than in the smaller scale of Fig. 1, the relative positions of the parts and the paths of theair and the fue Fig. 5` is a development of the heating 4 the standpipe, anda fioatin the bowl having a float valve operatively connected therewith for the purpose of maintaining an approximately constant level of fuel in the bowl. The space within the bowl is customarily termed the float chamber and will be so referred to hereinafter. Within the standtermed the needle valve.

pipe and extending thereinto from the mixing chamber is a valve adaptedto adjust the area of the passage from the float chamber to the mixing chamber and customarily The needle valve in thisinstance is provided with a passage throughout the entire length thereof. It is through this passage that the initial air y enters the float chamber at a point below the surface of the fuel therein.

Surrounding the standpipe, and separated therefrom by a cylinder of refractive material, is a heating drum provided with a helical passage therein adapted for the passage of the inf itial fuel-air mixture on its way from the float chamber to the mixing chamber. Surrounding the heating drum is a layer of refractive material, preferably ribbon mica, and over this is a heating element of chromenickel or similar wire. Surrounding the heating element is an enclosing cup-like cover of refractive material, preferably lava. One end of the heating element is grounded on the body of the carburetor, and the other end ofthe element is connected to a binding post.

In the preferred construction, as shown in the accompanying drawings, 6 is the body the float valve V15 for the admission of liquid fuel to float chamber 12. The bowl is held in place by means of theascrew 16, which is provided with a drain plug 17. The parts above enumerated are such as are generally to be found in carburetors of conventional design and are the fundamental parts to which my improvements areV applied.

Passing downward through the center of the mixing chamber and extending into float chamber at the center of the standpipe is the tubular needle valve 18. The needle valve is fitted with the double-ended control lever 19, riveted thereto. Near the lower end of the needle valve is a conical valve-seat 20. The needle valve is provided with a passage 2 1 drilled through the entire length thereof. Near the top of the valve is provided a cross passage 22, the area of which is controlled by the screw valve 23, by means of which the entrance from 22 to 21 may be partially or wholly closed.f The needle valve is surrounded with a lock nut 24 having a tapered thread thereon, and provided with saw slots 24', for purpose of clamping the needle and maintaining it in the position to which it has been adjusted. Near the lower end of the standpipe is a hollow screw 25 provided with the passage 26. The bore of the screw is slightly larger than the reduced end 18 of the needle valve, and a passage between the' two is thereby provided.

Surrounding the standpipe 10 and separated therefrom by the cylinder 32 is the heating drum consisting of the body 27, provided with the helical groove 28 in the form of a screwthread cut therein. vSurrounding the Vbody is the tubular cover 29 which is shrunk into place and the ends V3() thereof spun over the ends of the body. The conloa struction of the heating drum is best shown whole, the drum, asconstructed, formsV an `in the enlargedperspective Fig. 3. As a easily and cheaply manufactured substitute This thread 35 thereon. Vithin the case is the heater drum, which is slipped over the core 32. Above and below the heating drum are the washers 36-36 (Fig. 4) which close the ends of the drum. Since the flanges 30 do not entirely cover the ends of the helical groove, a space is provided forming the passages 3U/ 30' between ends of the heater drum and the washers.

Centrally of the standpipe there is provided a bore 10 closely fitting the main stem of the needle valve so that there is no passage between them at this point. The passage 10 -is enlarged at 10 by counterboring, and again at 10, forming passages in each instance between the needle valve and the inner wall of the standpipe. Ports 37-37 are provided by drilling through the standpipe into the counterbore 10 and corresponding ports 3S-3S by drilling through the standpipe into the counterbore 10. Ports37-37, to register with ports 8737, are drilled through the core 32, and similar ports 38-38 are drilled through 32 to register with ports 23S-88. Ports 37 and 38 provide communication with the passages 30', 30.

Surrounding the heater drum cover is a layer 39 of ribbon mica, and about this layer is wrapped the heating element 40, shown in flattened form in Fig. 5. The end 41 of the element is formed into an eye .41 for convenience in attaching it to the binding post 43, while the end 42 is bent at a right angle. As shown in Fig. 2, the end 42 is clamped against the body 6, being laid in a groove suitably provided in the top of the heater case. The actual position of the end 42 is about 150O of arc from the position shown, this position being chosen for the purpose of illustration. A conventional battery is shown at 45, one terminal of the .battery being attached to binding post 43,

and the other terminal grounded on the body 6. It is obvious that a switch and a rheostat may be inserted in the battery leads without departing from the purpose of the invention. Insulation of the binding post from the body is secured by insulation 44. The heating element may be packed about with fibrous packing 40', usingk asbestos, powdered mica or similar refractive ma.- terial.

In Fig. 1, just to the right of throttle 9, is a small ball valve 46 for the admission of air to the fuel-air mixture to aid in maintaining the economy of fuel when operating at or near full load. The use of such a valve is not new in the art and is illustrated as showing a completed practical ments shown, and in addition the adjustment of the initial air inlet valve 23, and the heating of the drum 27. With gasoline, the current is turned into the heating element just before starting the engine, and may be turned o soon after the engine is started, when the atmosphere is comparatively warm. When using the heavier fuels such as kerosene, the current is allowed to flow through the yheating element continuously. Vhen the engine is running, air for the initial mixture enters at 22, passes downv forms the fuel into vapor and raises it to a temperature that will effectually prevent condensation.

I claim Y 1. In a carburetor comprising a mixing chambena float chamber, a standpipe central of the float chamber, a tubular needle valve in thestandpipe and central thereof, a heater drum surrounding the standpipe, a helical passage provided in the drum, and passages in the standpipe so provided that they communicate with the passage in the drum in such manner that the mixture is compelled to pass from the float chamber through the helical passage on its way to the mixing chamber.

2. In a carburetor comprising a mixing chamber, a float chamber', a standpipe central of the float chamber, a drum surrounding the standpipe, a helical passage in the drum, passages in the standpipe providing communication from the float chamber to the helical passage, and other passages in the standpipe providing communication from the helical passage to the mixing chamber.

3. In a carburetor comprising a mixing chamber, a float chamber, a standpipe central of the float chamber, a drum surrounding the standpipe, a helical passage in the drum, passages in the standpipe providing communication from the float chamber to the helical passage, other passages in the standpipe providing communication from the helical passage to the mixing chamber, and an electrical heatingelement surrounding the drum. j

In witness whereof, I have hereunto affixed my signature.

JOHN S. SALVA. 

